The necessity and requirement for providing covers for the loads carried in the open boxes of vehicles such as haulage vehicles and dump trucks which use the public highways has been known for some time. This has been especially important when the vehicle is carrying a particulate, granular or lumpy material in its box, such as gravel, crushed stone, slag, salt or any mixture thereof, shredded scrap material of paper or metal, etc.; and is particularly so as to avoid damage to the road surfaces or following vehicles. In general, however, the covers which have been provided for open boxes of such vehicles--especially when the vehicle is of the tractor-trailer variety having a very large and long open box--have been very awkward to deploy and expensive to install.
The most usual cover which has been provided for open boxes of haulage vehicles has been a heavy tarpaulin construction which is simply mounted over the open box by spreading the cover along the box so that its edges overhang the sides thereof, and securing the edges at intervals along the length of the box with ropes or shock cords, usually made of rubber or other elastic material. However, such covers have proven to be unsatisfactory because the edges of the covers tend to flap if the vehicle is moving at high speed, and the deployment of the cover is very awkward if not nearly impossible to be done by one person. Since usually vehicles of the sort contemplated herein carry only one person, the driver, the open boxes of such vehicles have very often remained uncovered.
Other commercial covers for the open boxes of dump trucks and the like have been particularly of the sort taught, for example, in Sibley U.S. Pat. No. 3,549,199 issued Dec. 22, 1970, or White U.S. Pat. No. 3,656,802 issued Apr. 18, 1972. Each of those patents teaches a cover having a bail arrangement which is swingable so that the cross-arm of the bail can be moved from the front to the back of the open box, and carries with it a flexible cover. The cover may be guided on a plurality of cables, such as in the White device, or it may simply be secured to the bail with a crank arrangement to accommodate the re-winding of the cover material on an appropriate spindle or shaft. Such apparatus, however, is particularly useful only on short-bodied open boxes, because otherwise the bail must be very long. In any event, the vehicles of the sort contemplated herein may be very roughly handled and may be required to traverse rough ground, so that the likelihood of damage such as by mis-alignment of the swinging bail arrangement is very high. In such events, the cover is no longer deployable--or worse, has been deployed and must be cut away from the box to permit dumping of the load--and in any event such devices are very expensive.
It has been recognized, however, that a very simple solution to the problems noted above may be provided, and that solution takes into account the fact that, in nearly every instance, the driver of the haulage vehicle will probably climb into the open box of his vehicle to inspect the disposition of the load therein, and to spread the top of the load somewhat more evenly in the box so that it does not extend above the top edge of the box and so as to fill in along the sides where the material of the load has not flowed due to its own angle of repose. Thus, if there is a likelihood that the driver of the vehicle will at least inspect the load in the box of his vehicle, then an arrangement can be made for the driver to deploy a cover over the load in the box at the same time, provided that the cover is mounted in the box in such a manner that the driver alone can accomplish such action. Further, it has been recognized that the various state and provincial authorities who have licensing and regulatory authority over haulage vehicles of the sort contemplated herein are more stringently enforcing their regulations with respect to covers for open boxes of such vehicles and are introducing new regulations, so that liabilities exist if the load is not properly covered. It is therefore important to provide a cover which can be easily deployed, and also to provide indicator means to indicate to the driver and to the authorities whether or not the cover has been properly deployed.
Accordingly, this invention provides a cover assembly for the open boxes of haulage vehicles, dump trucks and the like, where the cover is a flexible material of any suitable construction, and is mounted in the open box by being secured at one end of the box and having its edges movable along guideways mounted on the side walls of the box near the top edges thereof. In such a manner, especially where the driver of the vehicle has entered the box to spread the top of the load, the cover can be deployed by the simple expedient of having the driver grasp the trailing edge of the cover and to walk from the one, stowing, end of the box to the other end of the box so as to deploy the cover over the load therein. When the cover has been deployed, it can be secured by any suitable means such as the attachment of a pair of shock cords of elastic material which hook onto any suitable hook retaining means at that end of the box.
The flexible material of the cover may be a tarpaulin material, or it may be a net or mesh material of suitable construction. Especially where the cover material is a net or mesh material, the mesh size is sufficiently small--as set out by regulation--to preclude passage therethrough of material from the load, but not so as to preclude passage therethrough of air. Thus, there is much less likelihood of the cover tending to billow or balloon as the vehicle is moving at high speed and as air may tend to permeate beneath the cover material.